


Under the Hood

by iqom



Category: Undertale (Video Game)
Genre: Alternate Universe - Horrortale, Blow Jobs, Ecto-Penis (Undertale), Fluff and Smut, Horrortale: Recovery AU, Illustrations, M/M, Smut, Sub!Mettaton, Teasing, Wire Play, dom!papyrus, heat - Freeform, papyton, sorta? more like, tongue jobs
Language: English
Status: Completed
Published: 2018-04-14
Updated: 2018-04-14
Packaged: 2019-04-22 16:17:37
Rating: Explicit
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 2,059
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/14312496
Author URL: https://archiveofourown.org/users/iqom/pseuds/iqom
Summary: Papyrus has taken it upon himself to make repairs on Mettaton; without Alphys' plans, he's flying by the seat of his pants, making new discoveries about Mettaton's body along the way...~fic by me, illustrations by MylCreates~~Horrortale: Recovery AU belongs to MylCreates~





	Under the Hood

**Author's Note:**

  * For [MylCreates](https://archiveofourown.org/gifts?recipient=MylCreates).



> hapty bifday Myl! Hope you have a great day! 
> 
> This fic comes as another birthday request I've taken in the Papyton discord; for the lovely Myl, a smut fic based on her AU Horrortale: Recovery, with some saucy illustrations as a basis ^^

Deep in the ruins of the empty Underground, a skeleton quietly tinkered on a robot in a decrepit and crumbling laboratory.

The prosthetic jaw was the newest thing. Papyrus had spent many sleepless nights on the surface crafting a titanium jaw as a surprise for Mettaton, whose own had gone missing years ago. Papyrus thought Mettaton looked beautiful no matter what, but Mettaton was clearly embarrassed by his tongue lolling from his face and the voice distortion his lack of a jaw caused. Papyrus had affixed it to Mettaton’s face with two large, unsightly bolts on either side and it didn’t move while he talked; even still, soft gratitude had shone in Mettaton’s rose quartz eye and in that moment Papyrus vowed to himself he’d make Mettaton whatever his heart should desire.

What started as project blossomed into a full-blown relationship; as Papyrus put the metal pieces back together, he collected the fragments of Mettaton’s broken soul. He started with Mettaton’s legs-- scraping off layers of rust, oiling the joints until they bent at the knee without flecks of old paint littering the cracked linoleum floor, re-varnishing his shapely metal calves and washing his soft silicone thighs until they gleamed in the low light-- and made his way up the robot’s body with little hinderance until he finally reached--  
Papyrus exhaled slowly, the air whistling between his teeth, as he brought the overhead lamp to Mettaton’s rusted chestplate. He had purposely avoided working on it for the last few months due to his nervousness about the puzzling mess of circuitry that was surely beneath it; it _needed_ to be checked for frayed wires and loose bolts, but Papyrus was loath to admit that the complicated technology was a complete and total mystery to him. If only there had been plans left behind somewhere in the lab…

Papyrus unscrewed the bolts holding the chestplate in place and set it carefully to the side. _Christ almighty_ , it was more of a mess than he thought. His hand hovered over the tangled, discolored wires, trying to decide what general area of the circuit board to begin messing with.

“Are you sure you know what you’re doing?” Mettaton asked, a teasing smile on his face. He knew Papyrus would never admit otherwise.

“Of course!” said Papyrus cheerfully, as expected. “As you may or may not be aware, the Great Papyrus is an expert at puzzles, especially those pertaining to mechanics!”

“I’m aware,” Mettaton giggled.

A particularly old-looking, rusted out wire cap caught Papyrus’ eye and he focused his attention on that. “I’m going to try to pull this out, okay? I’ll be keeping a close eye on the soul datalog to make sure your internal processes stay normal!” Papyrus indicated the steadily beeping machine next to them, hooked to Mettaton’s upper back by a rather complicated set of ropes and wiring that Papyrus had very proudly designed himself.

“I’d trust you with or without the datalog,” Mettaton said, his voice tender. Papyrus beamed at him, soul swelling behind his ribs, before putting his full attention to the task at hand.

He hooked his thin pointer phalanx around the wire and tugged, gently, testing its hold.

Mettaton inhaled sharply, the datalog’s wavelength vector leaping up with a shrill cry of protestation. Papyrus drew back his hand, alarmed. “What happened?!”

Mettaton stared down at his chest, eyes wide and jaw slackened. “I don’t know...t-try… try that again?”

  

In truth, Mettaton knew exactly what happened. Yes, it was certainly a surprise, but the delicious, tickling sensation that scampered up his spine-- and plunged down to between his legs-- was indicative of a rather unmistakable feeling.

Touching those wires was pleasurable to him. Sexually.

Who knew that the wires behind his chestplate were so… so _sensitive?_ In _that_ way? Mettaton was certainly unaware; his chestplate hadn’t been removed in what seemed like eons.

The heart monitor was quickening with every passing second as Papyrus’ fingers inched back towards the mess of wires. Mettaton struggled to even out his breathing; he didn’t want to embarrass Papyrus. But, _god… that felt…_

Papyrus pulled out the wirecap and it sparked with a loud popping noise; Mettaton’s back arched, his whole body tensing up, biting down hard to keep a cry of delight from escaping his throat. The semblance of it leapt from between his clenched teeth, creating a sort of strangled whine.

Papyrus looked taken aback, staring at Mettaton, the gleam of surprise illuminating the hollows of his eye sockets. Mettaton avoided his gaze sheepishly.

“D-did that… feel good?” Papyrus asked after a moment of thought. His voice was uncharacteristically quiet and warm.

Mettaton felt his face grow hot; a small gust of wet steam hissed from his cheek vents. _Yes, darling, oh my god,_ “I don’t know--”

But Papyrus was already reaching forward again, with both hands this time; his fingertips traversed the circuit board, snagging on the tiny wires, caressing the rusted eyelets. Mettaton whimpered, his hips rocking ever so slightly from side to side as his groin began to throb almost painfully in the confines of his latex leggings. The pleasure was surging through his synthetic veins-- liquid, creamy, delicious-- lighting up his eyes and melting his soul in its capsule.

He barely noticed Papyrus slip behind him until he was already there, pressing his pelvis firmly against his shapely behind; his left hand stayed entangled in his motherboard as he dragged the right one down Mettaton’s side until he could pinch and tease the soft silicone of his hips and thighs.

“Hmm… this is interesting!” Papyrus nudged Mettaton’s leggings down his thighs, his voice serious with just a hint of mischief,  “It seems as though, for some reason, the motherboard in your chassis has connections with your sexual organ… I think we may need to give this a test run!”

_Fuck, he’s teasing me…_ Mettaton was starting to feel rather dizzy as he allowed his legs to fall open, shuddering with anticipation as Papyrus drew the palm of his hand slowly, slowly up his gleaming purple length, before wrapping his fingers around it and grasping it loosely.

“I-Is it working, Mettaton?” Papyrus murmured, clearly faking an innocent interest in the heart monitor (which was reaching critical levels; flashing and beeping, the vector leapt to the top of the screen and skyrocketed back downwards with every beat of Mettaton’s shivering soul), “I can’t quite tell from the datalog…”

“ _Ah!_ ” Mettaton gasped as Papyrus pumped his hand experimentally, “Uh… maybe you should k-keep going, Pah-Papy. I-- _uh_ \-- can’t tell!” _Two can play this game, Papy-darling… as long as you don’t stop, please…_

                              

As soon as Papyrus noticed that Mettaton’s chest was sensitive not unlike his own ribs, his plans involving fixes and derusting were tossed to the wind as he began to formulate a much naughtier one: take Mettaton right up to the edge but no further.

Something about Mettaton’s unwillingness to openly capitulate to his pleasure was really getting Papyrus worked up in the best kind of way.

No, he wasn’t stupid; yes, he knew exactly what he was doing to Mettaton. Driving him insane. In past experiences, Papyrus learned that Mettaton was very easily teased and toyed with, he could be wound up like an alarm clock-- no, a _bomb,_ set to explode-- and the longer the robot tried to hold out the more frenzied he would become until he entered a state of boiling heat…

That was just too much fun to pass up.

Flecks of magic were rising from his bones as the viscous fluid of his soul began trailing downwards, coiling first around his ribs and then his pelvis until it pooled in the center, hardening swiftly against Mettaton. “You don’t have to hide it from me, my star,” Papyrus muttered, holding Mettaton a little closer, rolling his hips against him a little harder, “I want to make you feel good!” With that, he graced Mettaton’s neck with a quick nibble, and the robot convulsed in his arms.

“Look w-wh-w… _look--_ ”

“What’s that?”

“ _Look w-what you’re doing… d-doing to me..."_

Papyrus rotated his wrist and Mettaton’s hips rammed upwards, losing control as he began fucking the rough, tight space of Papyrus’ fist. “Make me cum… _please make me cum…_ ” The robot was half-rabid in his lusty hysteria--

Papyrus grinned, almost evilly, and stood up at once, leaving Mettaton a shivering puddle on the floor. “Not yet, my sweet! You’ve gotta earn it!”

Mettaton turned his blazing eyes upwards, staring hungrily as Papyrus unbuckled his pants and allowed his erection to spring free. The sight of it-- long, girthy, shining in the low light and illuminating his pitted femurs-- seemed to push Mettaton to new heights of desire; the robot sprang forward like a predator on the hunt, pushing Papyrus against the wall, tongue lapping ferociously at his leg bones and pelvis. Papyrus laughed breathlessly at Mettaton’s fervor, the sound falling away to wetness and gasping as Mettaton’s eager tongue slithered up his length…

“W-wait…” Mettaton panted, drawing back, “My jaw…”

He had a point. The clunky metal jaw was hardly the right equipment for such an endeavor.

“Take it off,” Mettaton continued, pulling at the jaw as if he expected it to pop off in his hands, “I don’t need a bottom lip for this.”

Papyrus blinked. “R-Really?”

Mettaton whined, bouncing impatiently on his knees. “Please trust me…”

Papyrus pulled his multitool from his shirt pocket and flicked out the screwdriver. “Alright, then, come here…”

His hands shook in anticipation as he unscrewed the tiny bolts that held the jaw in place and put them carefully one by one in his pocket. When the piece finally came free, Mettaton took it and set it down on the floor beside them before rising back up on his knees again, mulling over the task at hand…

Leaning forward and taking Papyrus’ pelvis in his hands, he slid his long, dexterous tongue along the underside of the magic cock, his upper lip dragging along the top. Papyrus grunted, allowing his hands to become tangled in the thicket of Mettaton’s hair. Mettaton was right; he was doing just fine-- more than fine, it was wet, sloppy, fantastic, just like a proper blowjob should be-- without a jaw.

****

Mettaton relished in the soft pressure of Papyrus’ pelvis against his face; he continued working his tongue, allowing Papyrus’ quickening breath and increasingly shrill gasps and moans to dictate his pace and intention of movement. Soon enough, Papyrus was rocking his hips into Mettaton’s mouth; his eyes slid upwards in time to catch Papyrus’ head fall back in a euphoric trance.

His own cock was crying for attention; no longer able to resist, Mettaton allowed a hand to trail downwards until he was tending to it at an equal pace of the ministrations of his mouth; pumping, sucking, licking, releasing strangled moans around Papyrus that only drove the skeleton closer to his release.

“ _Ah… ah…. Mettaton… I’m--ah! I’m close…”_

Mettaton purred gleefully around his mouthful, speeding up, focusing even more intently on his task. Now _he_ was the one in charge; but he had no desire (or patience, really, at this point Mettaton felt as though his body would combust if he didn’t finish soon) to tease Papyrus like Papyrus had done him. He implored Papyrus to orgasm with his tongue, curling it with fierce determination around him, bobbing his head, quickening his pace...

“ _Metta-- METTA-A-AH!”_

Papyrus finished, hard, spilling down Mettaton’s throat; Mettaton delivered the final pumps of his fist that he needed to bring himself over in hot pursuit.

Spurting, whimpering, the couple came to a juddering halt before both slunk down to the floor in a wet, exhausted tangle of arms and coils.

The two lay in enamored silence for a while; enjoying the curvature of the other's body, listening to each others' breathing and relaxing to the steady beeping of Mettaton's heart monitor, which was slowing down with every passing second. 

“Mettaton?” Papyrus murmured, nuzzling into the crook of his neck and wrapping his skeletal arms around him.

“Mmm…”

“I do still really need to work on your chestplate. Not now. But, like, at some point.”

Mettaton chuckled, cupping the back of his skull lovingly. “Of course, darling. We’ll get there.”

Moving to his mouth, Papyrus nibbled on Mettaton’s top lip. “We’ll… get there…”

   

**Author's Note:**

> https://iqomton.tumblr.com/


End file.
